Process for flotation of ores



. 15 ore body,

Patented Aug. 6, 1929.

PATENT OFFICE.

ADOLPHE H. NEY, OF NEW YORK, N. Y.

PROCESS FOR FLOTATION F ORES.

No Drawing.

This invention relates to a new and improved process for theconcentration of ores by the method known as froth flotation andparticularly to the use and employment in said ore concentrationprocess, of chemicals and substances and transformation productsthereof, hitherto unknown as being 0 advantage or utility as agents orassisting an auxiliary substances in said ore concentration process ascustomarily practiced. The process of concentrating ore, commonlydesignated froth flotation consists in producing by suitable means uponthe surface of an aqueous suspension of a finely comminuted a froth.Under suitable conditions, this froth carries to the surface of theliquid, a concentrate containing a higher percentage of the metallic orother valuable constituents of the ore treated than it originallycontained. T is concentrate is continuously or intermittently removedand further treated to recover and purify its valuable constituents.

A varietyof substances has been hitherto proposed and employed as agentsor assisting and auxiliary media for producing the concentrating effect,or as they are called promoters and many of these substances are indeedeffective in a greater or lesser degree in that their addition to orpresence in the operation of flotation produces or effects the formationof a concentrate containinga higher percentage of the valuableconstituents ofthe ore than the latter originally contained. Therelative value of such flotation agents also depends on the amountnecessary to be eifective, and the time required to produce such eflect,and their price.

Examples of such promoters are, for instance, the products of thereaction of an excess of disulphurdichloride upon certain aromaticamines, an

' able constitution:

R being a substituted aryl radical. These products may be consideredasthe intramolecular anhydrides, or sultams, of a substitutedthiosulphanic acid: R.S.S0.0H., R beposition by the amino group.

I have discovered that a group of comsponding sulphates,

d which have the proban aryl radical, substituted in the ortho-- seesthe constitution:

Application filed May 2, 1927. Serial No. 188,397.

pounds closely related structurally to the above and hitherto notemployed or proposed for thls purpose are very efiicient flotationagents. These compounds are derivatives of thiosulphuric acid HS:SO.OH-or its salts: l\IES.SO,.OMc, in which the hydrogen or metal-atom ofthe'sulphhydrate group: SH (SMe) is substituted by an organic radical.The prototype thiosulphate C .H .S.SO .ONa, has been discovered anddescribed by Bunte, Berichte der deutschen chemischen gesellschaft, 7,(187 4;), 64:6 and he as well as later investigators have prepared anddescribed other members of this group, such as n-propyl-, iso-butyl-,amylthiosulphate, as well as benzythiasulphate. Co1upare:ber.7 (1874;)1162; (Spring) .-15. (1882). 1938; (Spring and Legros).25. (1892). 988-;26 (1893) 993.996; (Otto and Rossing).-41 (1908) 1650; (A. Gutmann); 42(1909) 228 (A. Gut1nann).-Trans. Chem. Soc. 91 (1907) 2021; 93 (1909).1395, 1401; (Price and Slater) .Gazz. Chim. It.- 20, (1890). 25(Pu'rgatti).

Representatives of these groups of compounds may be prepared by allowingan alkylor arylalkyl-halide, such as ethylbromide or benzylchloride toreact upon sodiumthiosulphate in aqueous or aqueous-a1- coholic solutionat temperatures from 30 C. to 100 C. In place of the halides the correasfor example, sodiumethylsulphate or diethylsulphate may be used withequal success; also, the alkyland arylalkyl-radicals may be substitutedwithother groups such as the hydroxy-, alkyloxy-, carboxy-, sulpho-,amido-, cyan-, etc., group. If the alkyl group is-substituted by afurther negative group, such as halogen, it is possible, according tothe conditionsemployed, to replace either one or both of the negativegroups by the thiosulphuric-rest, as for instance with ethylendibromideboth: 1 Y

may be obtained without difliculty.

By allowing an organic acidhalide, such as benzoylchloride,acetylchloride, etc., to react in an analogous manner withsodiumthiosulphate, analogous compounds possessing similar propertiesmay be obtained. They pos- R.C.O.S.SO,.ONa. R

indicating an alkyl, aryl or arylalkyl group,

. which may be substituted.dihalides of ditively.

By reacting the chlorides of organic sulphonic acids,for exampleparatoluosulphochloride with sodiumthiosulphate, bodies of similarproperties having the probable constitution: R.SO .S.SO .ONa can beobtained.

Aromaticor purely aromatic-analoga of these compounds: R.S.S0.0Na andM050 S.R.SO .ONa, in which R a substituted arylgroup can also beobtained although by different reactions. Negatively substituted cyclichydrocarbons such aschlorbenzol, do not react With sodiumthiosulphatebarring certain exceptions.-Aromatic compounds capable of assuming, orpossessing, quinoid character,

however, as a rule, smoothly react with thio-- sulphate under formationof substituted aromatic thiosulphates of the type:

a 7 NH, mu-c 11 S.SO .ONa

"Patent. 47 92 of 1900.

Similarly, benzoquinons, hydroquinons and their substitution products,especially chlorsubstitution products react under suitable conditionswith one or several molecules of sodiumthiosulphate under formation ofhydroquinone-monothiosulphate, hydroquinonedi-thiosulphate andhydroquinone-tetra-thiosulphate, which on oxidation yield thecorresponding quinonemono or polythiosulphonic acid, or the corresonding di- 'or polysulphides. Compare: erman Patent. 175070.

These compounds are, in form of their alkali salts, in general, wellcrystallizing bodies, easily soluble in water and, though less readily,in alcohol. Under the influence of reducing agents, or even under theinfluence of hydrollzing agents, such as diluted mineral acid at theboil, they are transformed into the corresponding thiophenols, whileupon treatment with oxidizing agents, they yield according to the natureof the oxidizing agent used and the experimental conditions diorpolysulphides, presumably, for instance, according to the followingequation:

2R.S.SO .ONa+O+H O= nssmeuanso may be substituted.The solubility ofthese compounds in water decreases with the increase of their molecularweight, as does their stability, evidenced by an increased tendency toconversion into disulphidic form.

' I have prepared a considerable number of members, of this class ofcompounds, for exfication according ample: sodiummethyl-, sodiumethyl-,sodium-n-propyl-, sodium-iso-propyl-, sodiumiso-butylandsodium-iso-amyl-thiosulphate, by the reaction of the correspondingalkylhalids or alkylsulphates upon thiosulphate, in several instances byboth methods, and I have prepared benzylthiosulphate from benzylchlorideand thiosulphate; I have also prepared the reaction products ofsodiumthiosulphate with the following compounds: chloroacetic acid,glycerolmonochlorhydrinc, glyc erolmonochlorhydrine,glyceroldichlorhydrine, ethylendichloride (both one and bothchlorinatoms replaced by the thiosulphate rest) benzolsulphochloride,paratoluolsulphochloride and malonylchloride. When subjected toflotation testsall these compounds were found to be excellent promoters,particularly sodiumethylthiosulphate, sodium-isopropylthiosulphate, andsodiumbenzylthiosulphate.

sodium-isobutyl-thiosulphate the following example is given:

Example.

600 grs. of a sulphidic copper bearing ore containing'1.2% copper wereground to fineness of #60 mesh with some water, 5 grs.

slaked lime and 0.25 grs. sodium-ethyl-thiosulphate added and themixture transferred to a flotation cell, diluted and aeration started.Pine oil was added in drops as needed to produce frothing and the frothremoved at intervals. Aeration was continued for 30 minutes, whereuponthe collected froth was filtered and dried. It weighed, when dry, 67grs. and contained 10% of copper; an ex traction of 93.2% of the copperpresent having thus been effected.

When replacing in parallel tests the sodium-ethyl-thiosulphate bysimilar amounts of sodium-isopropylthiosulphate,sodiumisobutylthiosulphate and sodium-benzylthiosulphate, results veryclosely approximating that described above were obtained.

It is understood that my invention is not limited to the proportions ofmaterials given nor to the nature of subsidiary agents employed. Neitherdo I wish to be restricted to the use of any particular method or modusof working or operation, or to-any particular type of apparatus ormachinery, all these things being capable of variation and modito thenature of the ore treated and the result desired. It is further to beunderstood that my invention is not limited to the compoundsspecifically mentioned herein, nor to those which I have actuallyexamined as to their efficiency as fiotation agentsviz: 27 differentcompounds of this classbut I wish it expressly to be understood that myinvention includes all and any I it by replacement of the hydrogen ormetalgroup by an organic aving the constitu- R-S-fi-O-Me R being anorganic radical, which may be substituted and may contain thethiosulphate rest a second time or more times.

Their general efficiency as promoters in ore flotation appears to be-andprobably isdue in part to their tendency to assume under 'oxidativeinfluences, disulphidic form.

When employing these compounds as flotation agents, it is not necessarythat they be pure; excellent results, for instance, are obtained whenthe crude mixture obtained from the reaction of one molecule ofsodiumthiosulphate and molecule of (liethylsulphate, consisting ofapproximately 70% sodiumethylthiosulphate and 30% sodiumsulphate, isused as flotation agent. It is evident that this point is of greatimportance in regard to the economy of the process, and cost ofmaterial. v

Having thus described the nature of my said invention and in what mannerit may be applied, I declare that what claim is:

1. The method of concentrating ores by froth flotation which includessubjectingthe crushed mineral to a froth floating process I in thepresence of a derivative of thiosul- "phuric acid, in which the hydrogenatom of the sulphydrate group is replaced by an alkyl group. r

2. The method of concentrating ores by froth flotation which comprisessubjecting themineral in form of an alkaline pulp to a froth flotationoperation in the presence of sodiumalkylthiosulphate and a suitablefrothing agent.

3. The method of concentrating ores by froth flotation which comprisessubjecting the mineral in the form of a pulp rendered alkaline with limeto a froth flotation operation in the presence ofsodiumalkylthiosulphate and a suitable frothing agent.

In testimony whereof I affix my signature.

ADOLPHE H. NEY.

